Resuscitation,
24 (1992) 11-25
17
Elsevier Scientific Publishers Ireland Ltd.
A study of school students’ long term retention of expired air resuscitation knowledge and skills Phillip J. Moorea, Ronald C. Plotnikoffb and Gregory D. Preston” ‘Department of Education, University of Newcastle, New South Wales 2308 and bNational Health and Medical Research Council (NH+MRC). University of Newcastle, Centre for Clinical Epidemiology and Biostatistics, Faculty of Medicine, University of Newcastle, New South Wales 2308. Australia.
(Received April lOth, 1992; accepted May 1lth, 1992)
This study addresses the issue of the long term retention of Expired Air Resuscitation (EAR) knowledge and skills. The subjects were one hundred and two secondary school students, half of whom had received training in EAR procedures 5 years prior to this study. Data were collected from these subjects in relation to their knowledge of the EAR procedures and their ability to implement these procedures. In general the students who had undergone the EAR training 5 years ago performed better in the practical tasks than did their untrained counterparts. While there was virtually no difference in the theoretical knowledge section overall, the trained group did perform better on a number of questions. Key words; expired air resuscitation; retention; school students
INTRODUCTION
Knowledge of resuscitation is becoming an essential component of everyday life as it is likely that many deaths could be prevented by bystanders having knowledge of resuscitation procedures 1*6. The logical time to educate our society with resuscitation knowledge and skills is at the school age level, although there is some debate about whether or not cardiopulmonary training should be conducted with primary grade children. There is, however, little debate regarding the training of primary grade children in expired air resuscitation (EAR). Indeed, several local councils in the Hunter Region of New South Wales Australia have been involved in the training of such children through council operated EAR schemes. Research with high school students and with 1l- and lZyear-old primary school students revealed that school students can be trained in CPR. However, delayed testing (live months in Plotnikoff and Moore, 1989, see Ref. 8) showed performance declines in both knowledge and skills when compared to appropriate controls 1,8-1o. In the EAR domain, research with 11 and 12 year olds showed that regardless of scholastic ability and sex, these students are able to adequately learn, perform and Correspondence to: P.J. Moore, Associate Professor, Department of Education, University of Newcastle, New South Wales, Australia 2308. 0 1992 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
0300-9572/92/$05.00
18
retain the knowledge and skills related to resuscitation7. These data cover a period of 1 year after initial training. In a sense, the information we currently have regarding the effectiveness of resuscitation training in school contexts is limited. Our search of the literature informs us that no study has extended the examination of programme effects beyond a l-year period. Clearly this leaves unanswered the question of the durability of training. What are the longer term effects of training students at age 12? By, say 17 years of age, has the knowledge declined to an extent that makes performance of EAR ineffective? what of the appropriate sequencing of skills? These are non-trivial questions as individual lives may be determined by the need to unexpectedly perform resuscitation. The research undertaken here attempts to address this rather serious gap in current understanding of the longer term effects of an EAR training programme. Specifically, the study assesses EAR knowledge and skill levels of students 5 years after initial training. METHODOLOGY
Subjects
The subjects used in this study were 102 secondary school students in year 11. Fifty-one of these students were selected from the pool of students who were trained and tested in EAR procedures in the Plotnikoff study (the experimental group)7. The students were trained in 1984. The remaining 51 subjects were selected from secondary school students who had undertaken no such training (the control group). An analysis of the socio-economic status of the two groups showed no significant differences between them on this dimension. An examination of both groups’ high school life saving experience also showed no differences. Indeed, both groups had received approximately 2 days of instruction across their high school careers. Materials
The materials used in this study were similar to those used in the previous study by Plotnikoff in 1986. The test used to elicit information on the EAR knowledge of the subjects was the 14 item test used in the above study. This test consisted of 14 multiple choice items eliciting information on correct EAR technique, breathing patterns and reactions to common EAR problems. Discrete and continuous psychomotor skill information was also collected. A sequence order check list was used to record details of the subject’s actions on encountering a victim which are performed only once (discrete psychomotor variables). A total of seven variables were examined which assessed if the subject checked the consciousness and condition of the patient, correctly positioned and prepared the patient and whether or not five quick (full) breaths were administered. Resuscitation skills which are performed repeatedly (continuous psychomotor skills) were measured in two ways. Firstly by observation to determine if the subject had performed a safe head tilt grip, maintained an adequate seal and checked for escaping air after each ventilation. The number of attempted ventilations was also recorded.
19
The second method of collecting information on the continuous psychomotor skill of ventilation was through the use of a recording ‘Resusci-Anne’ manikin. Data over two minutes were recorded from this device. Specifically, the number of registered ventilations (> 0.00 litre), the number of adequate ventilations (> 0.8 1 and < 2.0 1) and total volume (in litres) of registered ventilations were recorded. From these data the percentage of adequate ventilations of those ventilations attempted, the percentage of adequate ventilations of those ventilations registered and mean volume (in litres) per registered ventilation were obtained. The time taken to deliver the first ventilation was also recorded. Procedure
The 14 item knowledge test was administered to both groups involved in the study on a group basis. Each individual was then tested independently for the psychomotor section of the study. In these individual tests a researcher observed the actions of the subject and recorded the discrete and continuous procedures undertaken. These results were matched with the printout from the recording ‘ResusciAnne’ manikin. This section of testing produced a duration of 2 min of EAR recording. Analysis
Data analysis was conducted to ascertain the differences between those students who had received training in EAR and those who had not. The major procedures used were variable frequencies and arithmetic means, Chi-squared analysis and T-tests using separate variance estimates owing to the general mean discrepancies between the groups. A probability of P c 0.05 was used to indicate significance. RESULTS
The results of the study fall mto two distinct areas: (1) the EAR knowledge test and (2) EAR psychomotor functions.
Table I.
Significant items and total score for knowledge test (standard deviations in parentheses).
Variable
Question 8 Question 12 Knowledge total (Max. 14)
Experiment
Control
group mean
group mean
1.0588 (0.242) 1.4118 (0.492) 10.8431 (1.977)
1.1961 (0.401) 1.6863 (0.468) 10.5882
(1.220)
*Significant at the P < 0.05 level.
F-value
Probability 2-tail
T-value
D.F.
2-Tail probability
2.85
0.000
-2.10
100
0.038*
1.12
0.679
-2.87
100
0.005*
2.22
0.006
100
0.452
0.75
20 Table II. Number of subjects performing each discrete EAR procedure. Note: The protocol instruction indicated that the victim had a heart beat, (percentages of total group performing procedure shown in parentheses). Procedure
Experimental group (N= 51)
Control group (N= 51)
1. Check if conscious - physical 2. Check if conscious - verbal 3. Turn to lateral or semi-prone position 4. Tilt head to open airway 5. Check mouth 6. Check for breathing by observing the chest 7. Check for breathing by listening and/or feeling for escaping air 8. Attempt live quick (Full) ventilations
8 (15.70) 5 (9.80) 17 (33.33) 36 (70.58) 35 (68.62) 26 (50.98) 12 (23.52)
13 (25.49) 5 (9.80) 10 (19.60) 27 (52.94) 25 (49.02) 18 (35.29) 13 (25.49)
0 (0.00)
4 (7.84)
EAR knowledge test While the mean score of the experimental group was higher than that of the control group, there was no significant difference between the groups on the basis of the overall score obtained in the EAR knowledge test conducted. There were, however, significant differences on the basis of two individual test items. In response to question eight, concerning the action to be taken if something is caught in the patient’s throat which cannot be removed with the fingers, the experimental group performed significantly better. Likewise, analysis of question twelve, relating to the length and timing of ventilations when giving EAR to an infant, showed that the experimental group was more likely to respond correctly. The T-test scores of these variables, along with the knowledge section total scores, are shown below in Table I. For each question the possible mean range was from one to two, with a mean of one reflecting that all students responded correctly. Thus a mean of two would reflect that no students responded correctly.
Table III.
Significant variables for discrete procedures (standard deviations are shown in parentheses).
Variable
Experimental group mean
Control group mean
Fvalue
Probability 2-tail
TValue
D.F.
2-Tail probability
Check mouth
1.3137 (0.468) 2.0000 (0.000)
1.5698 (0.504) 1.9216 (0.272)
1.16
0.600
-2.03
100
0.045*
1.12
0.680
100
0.042*
Attempt five quick (Full) ventilations
*Significant at the P < 0.05 level.
2.06
21 Table TV. First ventilation significance variable measured in seconds for those who attempted ventilations (standard deviations are shown in parentheses). Experimental group mean
Control group mean
24.6383 (20.56)
37.0238 (24.26)
F-value
Probability 2-tail
T-value
D.F.
2-Tail probability
1.45
0.231
-2.70
87
0.008*
‘Significant at the P < 0.01 level.
Performance of EAR psychomotor functions Discreteprocedures. Table II sets out the number of students from each group who
performed the preliminary procedures noted. The experimental group performed significantly better than the control group in checking the mouth. However the control group was significantly superior in attempting five quick (full) ventilations. The T-tests results for these two findings are set out below in Table III. For each of these variables the possible mean range was from one to two, with a mean of one reflecting that all students performed the procedure. Thus a mean of two would indicate that no students performed the procedure. For those who attempted to ventilate the victim, the experimental group took significantly less time to deliver the first ventilation than the control group as shown in Table IV.
Table V. Significant variables for observed continuous variables (standard deviations are shown in parentheses).
Safe head-tilt grip
Attempted ventilations
Experimental group mean
Control group mean
F-value
Probability 2-tail
F-value
D.F.
2-Tail probability
1.2045 (0.408) N=35 (69%) 24.8627
1.5116 (0.505) N=21 (41%) 20.2553
1.54
0.165
-3.12
85
0.002**
1.53
0.136
2.23
100
0.028;
‘Significant at the P < 0.05 level. **Significant at the P c 0.005 level.
22 Table VI. Number of subjects performing observed continuous procedure (non-significant variables) (percentages of total group performing procedures shown in parentheses).
Attempt to maintain an effective seal: Blocking nostrils with fingers or cheek Mouth to mouth or mouth to nose contact Check for escaping air after each ventilation: Observation of chest Listening and/or feeling with cheek at victim’s mouth
Experimental group (N=51)
Control group (N = 51)
47 (92%) 47 (92%)
44 (86%) 44 (86%)
33 (65%) 33 (65%)
32 (63%) 28 (55%)
Continuous procedures. The experimental group performed significantly better than the control group in seven of the 10 variables measuring the continuous psychomotor skill of ventilation. As seen in Table V, it was observed that the experimental group performed Table VII. T-tests of control/experimental groups’ variables measuring the continuous ventilation skill (data derived from the Resusci-Anne manikin) (standard deviations are shown in parentheses). Variable
Experimental group mean
Control group mean
F-value
Probability 2-tail
T-value
D.F.
2-Tail probability
Registered ventilation? Number of adequate ventilationsb Percentage adequate/ attempted Percentage adequate/ registered Total volume, registered ventilations (1) Mean volume registered ventilations (1)
10.5490 (13.60) 6.961 (10.436)
3.7255 (7.650) 2.196 (6.080)
3.16
0.000
3.12
100
0.002*
2.94
0.000
2.82
100
0.006*
27.9908 (36.46)
10.8543 (18.68)
3.52
0.000
2.96
100
0.005;
65.98 (25.786)
58.94 (37.277)
2.24
0.092
2.01
100
0.011’
11.9666 (16.684)
3.3764 (8.602)
3.76
0.000
3.27
100
0.001*
1.134 (2.34)
0.906 (2.66)
2.07
0.191
2.88
100
0.059
*Significant at the P < 0.05 level. aRegistered ventilations > 0.00 (1). bAdequate ventilations > 0.8 I 2.0 (1).
23
significantly better than the control group in performing a safe head tilt grip and attempting more ventilations. The possible mean range for the safe head-tilt was from one to two, with a mean of one indicating that all students performed the procedure, while a mean of two would reflect that no students performed the procedure. The other observed psychomotor skills (i.e. attempt to maintain an effective seal and check for air escaping after each ventilation) had no significant group effect. The number of students from each group who performed these procedures are given in Table VI. The data from the recording Resusci-Anne manikin (Table VII) revealed that the experimental group significantly performed a greater amount of registered ventilations, greater number of adequate ventilations, higher percentage of adequate ventilations that were attempted, higher percentage of adequate ventilations that were registered and greater total volume of the registered ventilations. Of the experimental group 37.25% administered 6 1or more air to the manikin as opposed to 9.8% of the control group. Although not reaching significance, the ‘Mean volume of Registered Breaths’, for the experimental group was still slightly higher than the control group mean. A large standard deviation detracted from the significance of this result. Further, a large number of the experimental group lost head tilt while performing this procedure which produced a result similar to that of students who had failed to tilt the head at all. This accounted for 15 subjects in the experimental group failing to ventilate the manikin. Fewer of the control group tilted the head and therefore this occurrence did not affect that group as much (three subjects from the control group lost head tilt). DISCUSSION
This study sought to examine the long term effects of a training programme of EAR on 1l- and lZyear-old children by means of assessing the knowledge and skills that were related to EAR. Generally it would seem that the group which received the EAR training has retained a substantial amount of information concerning EAR, especially in relation to the practical aspects of resuscitation, the actual performance of EAR. While this in itself is encouraging for the trainers involved in EAR, the nature of the subject being taught heightens the importance of even the smallest significance. Therefore, even the small differences reported in the knowledge section of testing should not be understated. Should the patient requiring resuscitation need such knowledge then the experimental group would be more likely to resuscitate successfully. This principle should also be applied to the psychomotor skills. In line with previous research the students had retained the continuous psychomotor skills of EAR7,*,“. The experimental group attempted more ventilations in the 2 min, a higher percentage of these ventilations were adequate and they inflated the manikin significantly more successfully. Further, the experimental group provided, on average, almost four times as much air to the victim as the control group in the 2-min period. The required amount of air that must be ventilated to
24
sustain a non-breathing adult is approximately 6 litres per minute5. The experimental group, by this criterion, were far more successful than their untrained counterparts. Thirty-seven percent of the trained group may have been able to sustain life, as opposed to the 9.8% successful resuscitation rate obtained by the control group. Further, this study reinforced the concern of poor backward head tilt performance as found in other studies3,4s9.Failure to tilt the head back or losing head tilt on the manikin was the basis of inadequate ventilation in 25 cases in the experimental group. In the case of loss of head tilt, which accounted for 15 subjects failing to ventilate the manikin sufficiently, it is worth considering that losing head tilt in an ‘actual situation’ may be minimal in comparison to the manikin’s difficulty in manoeuvrability. While the control group performed significantly better than the experimental group in performing the initial five ventilations on encountering the victim, this should not be overemphasised. First, there were only four students from the entire group who performed this action. Secondly, the experimental group had received no training in this particular aspect of EAR, as it was not recommended as part of the course to be taught to the 1l- and lZyear-olds in 1984. The fact that the experimental group did not perform better than the control group in their assessment of the victim’s condition, however, is cause for reflection. While it is possible that the artificial nature of the situation may have contributed to this result, it is clear that more emphasis on this aspect during training will help to improve the performance of resuscitators. RECOMMENDATIONS
The study has provided some useful insights into the retention of resuscitation techniques. It has validated, to a large degree, the efforts of EAR trainers operating with young adolescents. Further, the study has provided some evidence to support the expansion of the EAR program as well as providing direction for EAR refresher courses. Specifically, the study supports the following recommendations: (1) That there be continued instruction of students in EAR procedures in the upper Primary school, as the students clearly retain enough EAR skill to be signilicantly better resuscitators than those without training after 5 years. (2) That refresher courses be offered to students to reinforce the skills and knowledge components of EAR and to allow additional practice of the skills retained. (3) That refresher courses emphasise the following specific elements: (a) the importance of tilting the head to ensure ventilation, and (b) the importance of the initial, discrete procedures prior to continuous ventilations. (4) Administering five quick (full) initial ventilations could be implemented into EAR training at primary school level. ACKNOWLEDGEMENTS
This research was funded by a grant from Port Stephens Shire Council, Lake Macquarie Shire Council and the Royal Life Saving Society of Australia.
25 REFERENCES 1
Berkebile P, Benson D, Eroz C. Public education in heart-lung resuscitation: evaluation of three self training methods in teenagers. In: Proceedings for cardio-pulmonary resuscitation in emergency cardiac care. American Heart Association, 1975: 13-21. 2 Congalton AA Status and prestige in Australia, F.W. Cheshire Pty Ltd, Melbourne, 1969. 3 Korttila K, Vertio H, Savolainen K. Importance of using proper techniques to teach cardiopulmonary resuscitation to laymen, Acta Anaesthesiol Stand 1979; 23: 235-241. 4 Martin W, Loomis J, Lloyd C. CPR skills: achievement and retention under stringent and relaxed criteria. AJPH 1983; 73: 1310-1312. 5 Nunn JF. Applied Respiratory Physiology. Cambridge, UK Butterworth: 1989. 6 Peam J, Dawson B, Leditschke F, Petrie G. Who accepts first aid training? Aust Family Physician. 1980; 9: 602-605. 7 Plotnikoff R. Retention of expired air resuscitation skills of sixth class students. Environ Health Rev Aust 1986; 18: 35-49. 8 Plotnikoff R, Moore P. Retention of knowledge and skills in cardiopulmonary resuscitation of 11 and 12 year old children. Med J Aust 1989; 150: 296-302. 9 Van Kerschaver E, Delooz H, Moens G. The effectiveness of repeated cardiopulmonary resuscitation training in a school population. Resuscitation 1989; 17: 21 l-22. 10 Vanderschmidt H. Bumap T. Thwaites J. Evaluation of cardiopulmonary resuscitation course for secondary schools. Med Care (1975); 8: 763-774.
24 (1992) 11-25
17
Elsevier Scientific Publishers Ireland Ltd.
A study of school students’ long term retention of expired air resuscitation knowledge and skills Phillip J. Moorea, Ronald C. Plotnikoffb and Gregory D. Preston” ‘Department of Education, University of Newcastle, New South Wales 2308 and bNational Health and Medical Research Council (NH+MRC). University of Newcastle, Centre for Clinical Epidemiology and Biostatistics, Faculty of Medicine, University of Newcastle, New South Wales 2308. Australia.
(Received April lOth, 1992; accepted May 1lth, 1992)
This study addresses the issue of the long term retention of Expired Air Resuscitation (EAR) knowledge and skills. The subjects were one hundred and two secondary school students, half of whom had received training in EAR procedures 5 years prior to this study. Data were collected from these subjects in relation to their knowledge of the EAR procedures and their ability to implement these procedures. In general the students who had undergone the EAR training 5 years ago performed better in the practical tasks than did their untrained counterparts. While there was virtually no difference in the theoretical knowledge section overall, the trained group did perform better on a number of questions. Key words; expired air resuscitation; retention; school students
INTRODUCTION
Knowledge of resuscitation is becoming an essential component of everyday life as it is likely that many deaths could be prevented by bystanders having knowledge of resuscitation procedures 1*6. The logical time to educate our society with resuscitation knowledge and skills is at the school age level, although there is some debate about whether or not cardiopulmonary training should be conducted with primary grade children. There is, however, little debate regarding the training of primary grade children in expired air resuscitation (EAR). Indeed, several local councils in the Hunter Region of New South Wales Australia have been involved in the training of such children through council operated EAR schemes. Research with high school students and with 1l- and lZyear-old primary school students revealed that school students can be trained in CPR. However, delayed testing (live months in Plotnikoff and Moore, 1989, see Ref. 8) showed performance declines in both knowledge and skills when compared to appropriate controls 1,8-1o. In the EAR domain, research with 11 and 12 year olds showed that regardless of scholastic ability and sex, these students are able to adequately learn, perform and Correspondence to: P.J. Moore, Associate Professor, Department of Education, University of Newcastle, New South Wales, Australia 2308. 0 1992 Elsevier Scientific Publishers Ireland Ltd. Printed and Published in Ireland
0300-9572/92/$05.00
18
retain the knowledge and skills related to resuscitation7. These data cover a period of 1 year after initial training. In a sense, the information we currently have regarding the effectiveness of resuscitation training in school contexts is limited. Our search of the literature informs us that no study has extended the examination of programme effects beyond a l-year period. Clearly this leaves unanswered the question of the durability of training. What are the longer term effects of training students at age 12? By, say 17 years of age, has the knowledge declined to an extent that makes performance of EAR ineffective? what of the appropriate sequencing of skills? These are non-trivial questions as individual lives may be determined by the need to unexpectedly perform resuscitation. The research undertaken here attempts to address this rather serious gap in current understanding of the longer term effects of an EAR training programme. Specifically, the study assesses EAR knowledge and skill levels of students 5 years after initial training. METHODOLOGY
Subjects
The subjects used in this study were 102 secondary school students in year 11. Fifty-one of these students were selected from the pool of students who were trained and tested in EAR procedures in the Plotnikoff study (the experimental group)7. The students were trained in 1984. The remaining 51 subjects were selected from secondary school students who had undertaken no such training (the control group). An analysis of the socio-economic status of the two groups showed no significant differences between them on this dimension. An examination of both groups’ high school life saving experience also showed no differences. Indeed, both groups had received approximately 2 days of instruction across their high school careers. Materials
The materials used in this study were similar to those used in the previous study by Plotnikoff in 1986. The test used to elicit information on the EAR knowledge of the subjects was the 14 item test used in the above study. This test consisted of 14 multiple choice items eliciting information on correct EAR technique, breathing patterns and reactions to common EAR problems. Discrete and continuous psychomotor skill information was also collected. A sequence order check list was used to record details of the subject’s actions on encountering a victim which are performed only once (discrete psychomotor variables). A total of seven variables were examined which assessed if the subject checked the consciousness and condition of the patient, correctly positioned and prepared the patient and whether or not five quick (full) breaths were administered. Resuscitation skills which are performed repeatedly (continuous psychomotor skills) were measured in two ways. Firstly by observation to determine if the subject had performed a safe head tilt grip, maintained an adequate seal and checked for escaping air after each ventilation. The number of attempted ventilations was also recorded.
19
The second method of collecting information on the continuous psychomotor skill of ventilation was through the use of a recording ‘Resusci-Anne’ manikin. Data over two minutes were recorded from this device. Specifically, the number of registered ventilations (> 0.00 litre), the number of adequate ventilations (> 0.8 1 and < 2.0 1) and total volume (in litres) of registered ventilations were recorded. From these data the percentage of adequate ventilations of those ventilations attempted, the percentage of adequate ventilations of those ventilations registered and mean volume (in litres) per registered ventilation were obtained. The time taken to deliver the first ventilation was also recorded. Procedure
The 14 item knowledge test was administered to both groups involved in the study on a group basis. Each individual was then tested independently for the psychomotor section of the study. In these individual tests a researcher observed the actions of the subject and recorded the discrete and continuous procedures undertaken. These results were matched with the printout from the recording ‘ResusciAnne’ manikin. This section of testing produced a duration of 2 min of EAR recording. Analysis
Data analysis was conducted to ascertain the differences between those students who had received training in EAR and those who had not. The major procedures used were variable frequencies and arithmetic means, Chi-squared analysis and T-tests using separate variance estimates owing to the general mean discrepancies between the groups. A probability of P c 0.05 was used to indicate significance. RESULTS
The results of the study fall mto two distinct areas: (1) the EAR knowledge test and (2) EAR psychomotor functions.
Table I.
Significant items and total score for knowledge test (standard deviations in parentheses).
Variable
Question 8 Question 12 Knowledge total (Max. 14)
Experiment
Control
group mean
group mean
1.0588 (0.242) 1.4118 (0.492) 10.8431 (1.977)
1.1961 (0.401) 1.6863 (0.468) 10.5882
(1.220)
*Significant at the P < 0.05 level.
F-value
Probability 2-tail
T-value
D.F.
2-Tail probability
2.85
0.000
-2.10
100
0.038*
1.12
0.679
-2.87
100
0.005*
2.22
0.006
100
0.452
0.75
20 Table II. Number of subjects performing each discrete EAR procedure. Note: The protocol instruction indicated that the victim had a heart beat, (percentages of total group performing procedure shown in parentheses). Procedure
Experimental group (N= 51)
Control group (N= 51)
1. Check if conscious - physical 2. Check if conscious - verbal 3. Turn to lateral or semi-prone position 4. Tilt head to open airway 5. Check mouth 6. Check for breathing by observing the chest 7. Check for breathing by listening and/or feeling for escaping air 8. Attempt live quick (Full) ventilations
8 (15.70) 5 (9.80) 17 (33.33) 36 (70.58) 35 (68.62) 26 (50.98) 12 (23.52)
13 (25.49) 5 (9.80) 10 (19.60) 27 (52.94) 25 (49.02) 18 (35.29) 13 (25.49)
0 (0.00)
4 (7.84)
EAR knowledge test While the mean score of the experimental group was higher than that of the control group, there was no significant difference between the groups on the basis of the overall score obtained in the EAR knowledge test conducted. There were, however, significant differences on the basis of two individual test items. In response to question eight, concerning the action to be taken if something is caught in the patient’s throat which cannot be removed with the fingers, the experimental group performed significantly better. Likewise, analysis of question twelve, relating to the length and timing of ventilations when giving EAR to an infant, showed that the experimental group was more likely to respond correctly. The T-test scores of these variables, along with the knowledge section total scores, are shown below in Table I. For each question the possible mean range was from one to two, with a mean of one reflecting that all students responded correctly. Thus a mean of two would reflect that no students responded correctly.
Table III.
Significant variables for discrete procedures (standard deviations are shown in parentheses).
Variable
Experimental group mean
Control group mean
Fvalue
Probability 2-tail
TValue
D.F.
2-Tail probability
Check mouth
1.3137 (0.468) 2.0000 (0.000)
1.5698 (0.504) 1.9216 (0.272)
1.16
0.600
-2.03
100
0.045*
1.12
0.680
100
0.042*
Attempt five quick (Full) ventilations
*Significant at the P < 0.05 level.
2.06
21 Table TV. First ventilation significance variable measured in seconds for those who attempted ventilations (standard deviations are shown in parentheses). Experimental group mean
Control group mean
24.6383 (20.56)
37.0238 (24.26)
F-value
Probability 2-tail
T-value
D.F.
2-Tail probability
1.45
0.231
-2.70
87
0.008*
‘Significant at the P < 0.01 level.
Performance of EAR psychomotor functions Discreteprocedures. Table II sets out the number of students from each group who
performed the preliminary procedures noted. The experimental group performed significantly better than the control group in checking the mouth. However the control group was significantly superior in attempting five quick (full) ventilations. The T-tests results for these two findings are set out below in Table III. For each of these variables the possible mean range was from one to two, with a mean of one reflecting that all students performed the procedure. Thus a mean of two would indicate that no students performed the procedure. For those who attempted to ventilate the victim, the experimental group took significantly less time to deliver the first ventilation than the control group as shown in Table IV.
Table V. Significant variables for observed continuous variables (standard deviations are shown in parentheses).
Safe head-tilt grip
Attempted ventilations
Experimental group mean
Control group mean
F-value
Probability 2-tail
F-value
D.F.
2-Tail probability
1.2045 (0.408) N=35 (69%) 24.8627
1.5116 (0.505) N=21 (41%) 20.2553
1.54
0.165
-3.12
85
0.002**
1.53
0.136
2.23
100
0.028;
‘Significant at the P < 0.05 level. **Significant at the P c 0.005 level.
22 Table VI. Number of subjects performing observed continuous procedure (non-significant variables) (percentages of total group performing procedures shown in parentheses).
Attempt to maintain an effective seal: Blocking nostrils with fingers or cheek Mouth to mouth or mouth to nose contact Check for escaping air after each ventilation: Observation of chest Listening and/or feeling with cheek at victim’s mouth
Experimental group (N=51)
Control group (N = 51)
47 (92%) 47 (92%)
44 (86%) 44 (86%)
33 (65%) 33 (65%)
32 (63%) 28 (55%)
Continuous procedures. The experimental group performed significantly better than the control group in seven of the 10 variables measuring the continuous psychomotor skill of ventilation. As seen in Table V, it was observed that the experimental group performed Table VII. T-tests of control/experimental groups’ variables measuring the continuous ventilation skill (data derived from the Resusci-Anne manikin) (standard deviations are shown in parentheses). Variable
Experimental group mean
Control group mean
F-value
Probability 2-tail
T-value
D.F.
2-Tail probability
Registered ventilation? Number of adequate ventilationsb Percentage adequate/ attempted Percentage adequate/ registered Total volume, registered ventilations (1) Mean volume registered ventilations (1)
10.5490 (13.60) 6.961 (10.436)
3.7255 (7.650) 2.196 (6.080)
3.16
0.000
3.12
100
0.002*
2.94
0.000
2.82
100
0.006*
27.9908 (36.46)
10.8543 (18.68)
3.52
0.000
2.96
100
0.005;
65.98 (25.786)
58.94 (37.277)
2.24
0.092
2.01
100
0.011’
11.9666 (16.684)
3.3764 (8.602)
3.76
0.000
3.27
100
0.001*
1.134 (2.34)
0.906 (2.66)
2.07
0.191
2.88
100
0.059
*Significant at the P < 0.05 level. aRegistered ventilations > 0.00 (1). bAdequate ventilations > 0.8 I 2.0 (1).
23
significantly better than the control group in performing a safe head tilt grip and attempting more ventilations. The possible mean range for the safe head-tilt was from one to two, with a mean of one indicating that all students performed the procedure, while a mean of two would reflect that no students performed the procedure. The other observed psychomotor skills (i.e. attempt to maintain an effective seal and check for air escaping after each ventilation) had no significant group effect. The number of students from each group who performed these procedures are given in Table VI. The data from the recording Resusci-Anne manikin (Table VII) revealed that the experimental group significantly performed a greater amount of registered ventilations, greater number of adequate ventilations, higher percentage of adequate ventilations that were attempted, higher percentage of adequate ventilations that were registered and greater total volume of the registered ventilations. Of the experimental group 37.25% administered 6 1or more air to the manikin as opposed to 9.8% of the control group. Although not reaching significance, the ‘Mean volume of Registered Breaths’, for the experimental group was still slightly higher than the control group mean. A large standard deviation detracted from the significance of this result. Further, a large number of the experimental group lost head tilt while performing this procedure which produced a result similar to that of students who had failed to tilt the head at all. This accounted for 15 subjects in the experimental group failing to ventilate the manikin. Fewer of the control group tilted the head and therefore this occurrence did not affect that group as much (three subjects from the control group lost head tilt). DISCUSSION
This study sought to examine the long term effects of a training programme of EAR on 1l- and lZyear-old children by means of assessing the knowledge and skills that were related to EAR. Generally it would seem that the group which received the EAR training has retained a substantial amount of information concerning EAR, especially in relation to the practical aspects of resuscitation, the actual performance of EAR. While this in itself is encouraging for the trainers involved in EAR, the nature of the subject being taught heightens the importance of even the smallest significance. Therefore, even the small differences reported in the knowledge section of testing should not be understated. Should the patient requiring resuscitation need such knowledge then the experimental group would be more likely to resuscitate successfully. This principle should also be applied to the psychomotor skills. In line with previous research the students had retained the continuous psychomotor skills of EAR7,*,“. The experimental group attempted more ventilations in the 2 min, a higher percentage of these ventilations were adequate and they inflated the manikin significantly more successfully. Further, the experimental group provided, on average, almost four times as much air to the victim as the control group in the 2-min period. The required amount of air that must be ventilated to
24
sustain a non-breathing adult is approximately 6 litres per minute5. The experimental group, by this criterion, were far more successful than their untrained counterparts. Thirty-seven percent of the trained group may have been able to sustain life, as opposed to the 9.8% successful resuscitation rate obtained by the control group. Further, this study reinforced the concern of poor backward head tilt performance as found in other studies3,4s9.Failure to tilt the head back or losing head tilt on the manikin was the basis of inadequate ventilation in 25 cases in the experimental group. In the case of loss of head tilt, which accounted for 15 subjects failing to ventilate the manikin sufficiently, it is worth considering that losing head tilt in an ‘actual situation’ may be minimal in comparison to the manikin’s difficulty in manoeuvrability. While the control group performed significantly better than the experimental group in performing the initial five ventilations on encountering the victim, this should not be overemphasised. First, there were only four students from the entire group who performed this action. Secondly, the experimental group had received no training in this particular aspect of EAR, as it was not recommended as part of the course to be taught to the 1l- and lZyear-olds in 1984. The fact that the experimental group did not perform better than the control group in their assessment of the victim’s condition, however, is cause for reflection. While it is possible that the artificial nature of the situation may have contributed to this result, it is clear that more emphasis on this aspect during training will help to improve the performance of resuscitators. RECOMMENDATIONS
The study has provided some useful insights into the retention of resuscitation techniques. It has validated, to a large degree, the efforts of EAR trainers operating with young adolescents. Further, the study has provided some evidence to support the expansion of the EAR program as well as providing direction for EAR refresher courses. Specifically, the study supports the following recommendations: (1) That there be continued instruction of students in EAR procedures in the upper Primary school, as the students clearly retain enough EAR skill to be signilicantly better resuscitators than those without training after 5 years. (2) That refresher courses be offered to students to reinforce the skills and knowledge components of EAR and to allow additional practice of the skills retained. (3) That refresher courses emphasise the following specific elements: (a) the importance of tilting the head to ensure ventilation, and (b) the importance of the initial, discrete procedures prior to continuous ventilations. (4) Administering five quick (full) initial ventilations could be implemented into EAR training at primary school level. ACKNOWLEDGEMENTS
This research was funded by a grant from Port Stephens Shire Council, Lake Macquarie Shire Council and the Royal Life Saving Society of Australia.
25 REFERENCES 1
Berkebile P, Benson D, Eroz C. Public education in heart-lung resuscitation: evaluation of three self training methods in teenagers. In: Proceedings for cardio-pulmonary resuscitation in emergency cardiac care. American Heart Association, 1975: 13-21. 2 Congalton AA Status and prestige in Australia, F.W. Cheshire Pty Ltd, Melbourne, 1969. 3 Korttila K, Vertio H, Savolainen K. Importance of using proper techniques to teach cardiopulmonary resuscitation to laymen, Acta Anaesthesiol Stand 1979; 23: 235-241. 4 Martin W, Loomis J, Lloyd C. CPR skills: achievement and retention under stringent and relaxed criteria. AJPH 1983; 73: 1310-1312. 5 Nunn JF. Applied Respiratory Physiology. Cambridge, UK Butterworth: 1989. 6 Peam J, Dawson B, Leditschke F, Petrie G. Who accepts first aid training? Aust Family Physician. 1980; 9: 602-605. 7 Plotnikoff R. Retention of expired air resuscitation skills of sixth class students. Environ Health Rev Aust 1986; 18: 35-49. 8 Plotnikoff R, Moore P. Retention of knowledge and skills in cardiopulmonary resuscitation of 11 and 12 year old children. Med J Aust 1989; 150: 296-302. 9 Van Kerschaver E, Delooz H, Moens G. The effectiveness of repeated cardiopulmonary resuscitation training in a school population. Resuscitation 1989; 17: 21 l-22. 10 Vanderschmidt H. Bumap T. Thwaites J. Evaluation of cardiopulmonary resuscitation course for secondary schools. Med Care (1975); 8: 763-774.
